Some examples of storage cases are disclosed in JP-A-2004-186039, JP-A-2004-166413 and JP-A-2000-217227. Each of the storage cases includes a storage case body in which certain objects, such as electrical devices or equipment, are housed, and into which entry of water; or the like, from the outside is prevented or restricted. The storage case allows connection between the stored objects and other electrical devices disposed outside the storage case body.
The storage cases as described above employ a seal structure so as to allow communication with the outside of the storage case body while preventing or restricting entry of water, or the like, into the storage case body.
The storage case employing the seal structure includes an opening in which wiring for connecting the stored object(s) and the outside electric device(s) is provided, a closure member for closing the opening while allowing connection between the inside and outside of the storage case body and the seal structure that inhibits or restricts entry of water, or the like, into the storage case body through an interface between the storage case body and the closure member.
The seal structure includes a seal member, such as an O ring, which is sandwiched by and between the outer surface of the storage, case body and the closure member. In the presence of the seal member, a clearance is likely to appear between the closure member and the outer surface of the storage case.
The storage case employing the seal structure as described above provides a certain waterproof effect, and is thus often exposed to an environment where the storage case body is subjected to water, or the like.
In some cases, water containing foreign matter may contact a surface of the storage case body which is located above the opening of the storage case. Then, the water may flow downward on the outer surface of the storage case body, and enter the clearance between the closure member and the outer surface of the storage case body, resulting in contact of the water containing foreign matter with the seal member.
The water reaching the seal member is initially prevented by the seal member from moving into the storage case body, and the foreign matter contained in the water is deposited on the seal member. Then, the seal member may degrade with time due to the foreign matter deposited on the seal member, and the sealing surface pressure of the seal member may be reduced. As a result, the waterproofing function of the seal member may deteriorate, and water, or the like, may enter the storage case.
To avoid the above-described situation, the seal member may be formed of a highly functional material capable of withstanding the foreign matter. The use of the seal member, however, gives rise to a problem of increased cost.